- Data from infants that experience perinatal asphyxia, pathologic neonatal hyperbilirubinemia, respiratory disease, antibiotic therapy (aminoglycosides), CNS infection, sepsis, congenital or middle or external ear lesions, craniofacial anomalies, chromosomal disorders, TORCH (toxoplasmosis, other infections, rubella, cytomegalovirus infection and herpes simplex infection) or those that were clinically unstable with the first 48 h post-delivery will be excluded from ABR studies. Infants born to mothers with positive drug abuse screens at delivery will also be excluded from further study (these screens are automatically run among this age group). Infants that are identified with hearing deficits at birth using the OAE screening will be excluded from the ABR measures.